1. Field of the Invention
The present invention relates to an electrostatic recording apparatus, such as an electrophotographic copying machine, more specifically relates to an electrostatic recording machine having an improved cleaning device.
2. Description of the Prior Art
In an electrostatic recording apparatus, such as a transfer type electrophotographic copying machine, an electrostatic latent image is produced on an image forming member by projecting a light on an original to be copied and projecting a reflex light reflexed from the original to be copied on the image forming member, a visible image or toner image is obtained by developing said electrostatic latent image by using a developing agent including toner, and a copied image of the original is produced on a transfer paper by transferring and fixing said visible image on the transfer paper. In an electrophotographic treating carried out in the copying machine of this type, toner remains on the image forming member even after the transfer treating has been carried out and accordingly the residual toner must be removed from the surface of the image forming member prior to the next electrophotographic treating in order to prevent the image from being spoiled due to the residual toner. A device to be used for this purpose is called as a cleaning device and many kinds of such cleaning devices, such as of the type using a toner scraping member or using a feather have been proposed.
The cleaning device of the type using the feather has such a drawback that not only toner is scattered from the cleaning device and darts the device when the cleaning is carried out, but also the scattered toner is attached again on the image forming member to cause the spoiled image. Accordingly, the cleaning device of the type using the toner scraping member (refer to as blade hereinafter) has been recommended to use.
FIG. 1 is a schematic view of a cleaning device A of the type using a blade 2. As will be appreciated from the description hereinbefore, an electrostatic latent image is changed to toner image by developing means (not shown) on a photosensitive layer 1a mounted on a photosensitive drum 1 which is being rotated in the counter-clockwise direction. Then the attached toner is transferred by transfer means (not shown) on a transfer paper. Some of toner is remained on the surface of the photosensitive layer 1a after toner has been transferred. This residual toner is scraped off by a tip end corner portion 3 of the cleaning blade 2 and the scraped toner is guided along a toner guide member 4 and collected in cleaning device A. In case that the copying operation is carried out by using the copying machine having such cleaning device, toner and/or powder paper of the transfer paper is attached gradually according to the copying operation on the tip end portion of the blade. This causes the contact or squeeze relation between the blade 2 and the photosensitive layer 1a mounted on the photosensitive drum 1 becoming incomplete gradually and the good cleaning becoming impossible, thereby causing the transfer image to be spoiled.
In order to obviate such defects, there has been proposed to select the material of toner and/or blade to prevent toner from being attached on the blade. However, it is difficult to select suitably the material of toner and/or blade and the above problems have not yet been solved perfectly.
Other attempt has been made to solve the above problems. In this attempt, the blade is vibrated in a direction substantially normal to the rotary direction of the photosensitive drum to shake off the attached toner or powder paper from the blade. In this attempt, however, it is impossible to shake off perfectly the attached toner or powder paper from the blade and is necessary to provide further a device for vibrating the blade, resulting in the apparatus becoming complex and expensive.